AMD isn’t backing down from its PR offensive against Nvidia’s Gameworks, opening another front against Nvidia in a wide ranging interview with Maximum PC on Friday.

A month ago AMD first launched an attack against Nvidia, when AMD technology evangelist Robert Hallock accused Nvidia in a piece by Jason Evangelho in Forbes of deliberately crippling performance of Ubisoft’s new Watch Dogs title on AMD hardware. Nvidia denied most of Hallock’s claims, particularly that AMD was not allowed to see game code to work on its own drivers, but AMD is doing anything but backing down.

Speaking with Maximum PC’s editors, Richard Huddy says that while he hasn’t seen any exclusivity contracts from Nvidia specifically — as they are protected by NDAs — he has seen emails from various ISVs that mention these contracts as reason why these companies cannot work with AMD on optimizing the game’s code for AMD hardware.

“ISVs are being used as a “human shield,” he said. “This is not in the interest of PC games at all.”

A theme during the interview was AMD’s principle of openness with Mantle, which Huddy talked about in many different contexts, but in the context of Gameworks Huddy brought up Gameworks’ technical structure as why it’s toxic for the industry.

The Gameworks library, as Huddy explained, is closed source. It’s delivered to developers as pre-compiled DLLs (click the link for an explainer of what one is) which are patched into the game’s code to enable the specific effects.

But providing pre-compiled DLLs goes against the grain of industry trends in coding, said Huddy.

“In my career that began with 3D Labs in 1996, to date, I’ve never had a game developer ask me for a DLL [to be used in] games’ code. They would never ask for that, they would always ask for source code,” he said, explaining that having intimate access to code is more efficient than using pre-compiled DLLs.

This is problematic for AMD, because games with Nvidia-written DLLs are being used to benchmark AMD hardware — a major conflict of interest for even a casual observer.

“If Nvidia are the good guys, then maybe it’s alright for them to write code that benchmarks my hardware,” he said.

Batman Arkham Asylum was the first example of when this tactic was used.

But some might point at last year’s Tomb Raider and its use of TressFX as an example of AMD’s WatchDogs moment. Huddy said this isn’t the case, as the contract with this game’s developer, Crystal Dynamics, did not have an AMD exclusivity clause. To prove that, Huddy offered to put the contract out in the open in the future.

Huddy contrasted Nvidia’s approach with Gameworks to that of Mantle. Mantle, which takes a much different approach to the optimization problem, is, as one could gather from Huddy’s comments, entirely the opposite of Gameworks when it comes to openness and exclusivity.

“In Mantle we’re putting out a standard and inviting others to join in but they don’t need to if they don’t want to. There isn’t anything we could even to in a Mantle app that could conceivably even harm Nvidia,” Huddy said. “A games developer could choose to produce a Mantle only app. I don’t know of any doing so, and we haven’t asked anyone to. There’s no harm to Nvidia from Mantle. It’s about changing the way that game developers are able to expose the benefits of hardware.”

Interest from Intel?

As evidence to prove Mantle’s openness, Huddy said that Intel had approached AMD for access to the API.

“I know that Intel have approached us for access to the Mantle interfaces, et cetera,” Huddy said. And right now, we’ve said, give us a month or two, this is a closed beta, and we’ll go into the 1.0 [public release] phase sometime this year, which is less than five months if you count forward from June. They have asked for access, and we will give it to them when we open this up, and we’ll give it to anyone who wants to participate in this.”

Huddy didn’t have a timeline for Intel being given a copy of Mantle to experiment is, only stating that when Mantle leaves its current state of closed beta Intel can have a look.

For its part, Intel substantially plays down AMD’s claim of its interest in the API.

“Our hope was to build consensus on potential approaches to reduce overhead with additional data. We have publicly asked them to share the spec with us several times as part of examination of potential ways to improve APIs and increase efficiencies,” an Intel spokesperson is quoted as saying by PC World. “At this point though we believe that Dirext X 12 and ongoing work with other industry bodies and OS vendors will address the issues that game developers have noted.”

AMD has publicly offered Nvidia the ability to see Mantle when its ready, but Huddy thinks this offer will be rebuffed.